Vacuum Testing of the Miniature Radio-Frequency Ion Thruster

A miniature RF-ion thruster (MRIT) is being designed and developed at The Pennsylvania State University. It is a complete 2-grid ion thruster, composed of a xenon gas reservoir flowing into an ionization chamber surrounded by a RF coil, connected to a matching network, and fed by RF source. The MRIT has been tested in a vacuum chamber for plasma discharge power levels on the order of ten watts. A 13.56-MHz indus- trial unregulated frequency is used as the excitation frequency. With an input power of approximately 15 W and an acceleration grid voltage of approximately 1 kV, we estimate being able to obtain a specific impulse of approximately 3800 s and thrust in the 100s of µN. Estimates of thrust are calculated from measurements of the ion beam current, which are made via a Faraday cup. This paper describes the tests made to date on the MRIT. The MRIT is to be flight tested onboard LionSat, a Penn State student-designed satellite. The mission requirements for LionSat are a minimum of one hour of continuous operation for the RF-Ion thruster and a measurable change in the satellite rotation rate.